Water and Ice

Outline1. Introduction  2. The Hydrogen Bond  3. Tetrahedral Geometry4. Ice5. Water6. Melting

The Hydrogen Bond

The hydrogen bond is ubiquitous in biological systems. It plays an essential role in explaining the physical properties of water and in understanding of the three-dimensional structure of biological macromolecules.

An attractive interaction exists between the lone pair of the oxygen atom and the hydrogen atom in an O–N covalent bond. The attraction is strongest when the O–H bond is directed along the lone-pair orbital axis. The hydrogen bond is always long and weak compared to a covalent bond. [Notes]

the hydrogen bond between two water molecules. The hydrogen bond's length (O···H) is given in angstroms (1 Å = 0.1 nm). Compare it to the length of the covalent O–H bond.

between spacefilling and ball-and-stick models.

map of charges on and off.